From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753858AbeC1OcX (ORCPT ); Wed, 28 Mar 2018 10:32:23 -0400 Received: from mga17.intel.com ([192.55.52.151]:52188 "EHLO mga17.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753609AbeC1OcU (ORCPT ); Wed, 28 Mar 2018 10:32:20 -0400 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.48,371,1517904000"; d="scan'208";a="41445922" Message-ID: <1522247538.10197.3.camel@tzanussi-mobl.amr.corp.intel.com> Subject: Re: [PATCH] tracing: avoid string overflow From: Tom Zanussi To: Arnd Bergmann Cc: Steven Rostedt , Ingo Molnar , Rajvi Jingar , linux-kernel@vger.kernel.org Date: Wed, 28 Mar 2018 09:32:18 -0500 In-Reply-To: <20180328140920.2842153-1-arnd@arndb.de> References: <20180328140920.2842153-1-arnd@arndb.de> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.10.4 (3.10.4-4.fc20) Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Arnd, On Wed, 2018-03-28 at 16:09 +0200, Arnd Bergmann wrote: > 'err' is used as a NUL-terminated string, but using strncpy() with the length > equal to the buffer size may result in lack of the termination: > > kernel/trace/trace_events_hist.c: In function 'hist_err_event': > kernel/trace/trace_events_hist.c:396:3: error: 'strncpy' specified bound 256 equals destination size [-Werror=stringop-truncation] > strncpy(err, var, MAX_FILTER_STR_VAL); > > This changes it to use the safer strscpy() instead. > > Fixes: f404da6e1d46 ("tracing: Add 'last error' error facility for hist triggers") > Signed-off-by: Arnd Bergmann > --- > kernel/trace/trace_events_hist.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/kernel/trace/trace_events_hist.c b/kernel/trace/trace_events_hist.c > index 4f027642ceef..8357f36d7a1e 100644 > --- a/kernel/trace/trace_events_hist.c > +++ b/kernel/trace/trace_events_hist.c > @@ -393,7 +393,7 @@ static void hist_err_event(char *str, char *system, char *event, char *var) > else if (system) > snprintf(err, MAX_FILTER_STR_VAL, "%s.%s", system, event); > else > - strncpy(err, var, MAX_FILTER_STR_VAL); > + strscpy(err, var, MAX_FILTER_STR_VAL); > > hist_err(str, err); > } Yes, thanks for finding this, and for the patch! Acked-by: Tom Zanussi